Regenerative system of control.



ZMMM gg i@ No. 889,908. A EATENTED JUNE 9, 1908. W. COOPER.

RBGENERATIVE SYSTEM OE CONTROL.

APPLICATION FILED SEPT. 3,1907.

3 SHEETS-SHEET 1.

WITNESSES: INVENTOR TTORNEY mam.

No. 889,908. PATENTED JUNE 9, 1908. W. COOPER. vREGNERATIVE SYSTEM 0FCONTROL.

APPLICATION FILED SEPT. 3,1907.

s SHEETS-SHEET 2.

wnNEssEs: I.

No. 889,998. PATENTED JUNE 9, 1908. I W. 890888.

REGBNBRATIVB SYSTEM 0F CONTROL.

AFPLIGATION F L D s .8 19o I E EN 7 ssamm-SHEET s.

VWTNESSES:

ATTRNEY UNITED sTATEs PATENT OEEIOE.

WILLIAM COOPER, OF PITTSBURG, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSEELECTRIC :St MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

REGENERATIVE SYSTEM OFCONTROL.

y No. 889,908.

Specification of Letters Patent.

Patented .nine 9, 1908.

Application filed September 3, 1907. Serial No. 391,226.

-State of Pennsylvania, have invented a new and useful Improvement inRegenerative Systems of Control, of which the following is aspecification. y

My invention relatestov systems of control for electric railway motors,and particularly to systems in which the motors may be converted intogenerators to effect braking and to. restore power to the distributingcircuit.

The object of my invention is to provide a system of control in whichalternating current motors of the commutator type of construction may becaused to operate as generators and supply substantially a constant lamount of current to the distributing circuit irrespective of the speedof the motors.

A further object is to prevent the motors from being coi'mecte'd to thedistributing circuit except vwhen the electromotive forces generatedthereby are approximately equal to that of the distributing circuit,

If the field magnet winding of an alternating current ymotor of thecoiiimutator type is separately excited, the electromotive forcegenerated by the 'armature is approximately 900 out of phase with theelectromotive force applied to ltheiield magnet winding. For this reasonit has' been proposed to utilize one of the motors upon' a4 railwayvehicle as an eX- citer .for the remaining motors, the field magnetwinding of the vexciterbeing connected between suitable points in asubdivided main transformer, while the exciter armature is connected tothe field'magnet windings of the remaining motors, the armatures ofwhich are connectedv between suitable points in the main transformer. Itwill be und'erstood that the object of such an arrangement is to 'causethe generated electromotive force to' be nearly or approximately of thelsame phase as that of the distributing circuit. As the/speeds of themachines decrease or vary,

' "the 'generated electromotiye force may be maintained substantiallyequal to that be- Vtweer'i the points inthe main' transformer to whichthe generator armatures are connected rvby adjusting the voltage appliedto the field f =magnet winding ofthe exciter orfby altering theconnections between --tlie generator 'armatures and the maintransformer. In the -present system, the armatures of the motors currentsupplied to the distributing circuit is` maintained substantiallyconstant, irrespective of the speed of operation.

Figure 1, of the accompanying drawings, is a diagrammatic view of asystem of control that embodies my invention. Fig. 2 is a chart givingthe order of closure of the switches of the said system. Fig. 3 is asimplified diagrammatic view of the arrange'- ment of the main circuitsof the system when lthe motors are operated as generators. Fig. 4 is adiagrammatic view of a modification of the system of Fig. 1, and Fig. 5is a chart giving the. order of closure of the switchesin the system ofFig. r4.

The system comprises a main, subdivided auto-transformer winding 1 thatis supplied from any suitable circuit, such as a trolley conductor 2 anda track rail 3 of a railway 7, 8, and 9, respectively, and field magnetwindings 10, 11, and 12, respectively; 'a set of switches'l to'24,inclusive, for governing the direction of rotation of the motors;another set of switches 25 to 30, inclusive; for governing the circuitarrangement of the motors when operating the same as genera tors; a setof switches 31'to` 42, inclusive, for adjusting the connections of themotors with the main auto-transformer 1; a set of switches 43 to 52,inclusive,- for governing the connections of the field magnet windingsof lthe motors with the main auto-transformer winding when the motorsare operated as generators; three choke coils 53, 54, and 'th'at arearranged as set forth in Patent No. 834,525, granted October 30, 1906,to the Westinghouse Electric & Manufacturing Company, as assignee of-RayP.

Jackson, for the purpose of preventing in'/ voltage oi the the motorswith the m'ain 'auto-transformer into engagement therewith; a mastercon.

trollerforgoverning the circuits of the remaining operating orcontrolling magnet windings 60, the said masterv controller comprisingstationary contact terminals 66 to 89, inclusive, a movableconductingvsegment 90 that, for motor operation, is adapted to engagethe s aidstationary contact terminals upon position-indicating lines leto Z,` inclusive, and a movable conducting segment 91v that is adaptedto engage the-stationarycontact terminals upon position-indicating`lines a to. r', inclusive, 'n orden-to cause the inotors to operate asgenerators; a switch 92 interposed in the circuits of the operating orcontrolling magnet windings-oi the switches 25 and 28'and`having anoperating orcontrolling magnet winding'93 that is connected 'between oneterminal of the motor armature 5 and the neutral point of the choke coil55, 'the said switch closing', and in turn permitting 'closure oiswitches 25 andl 28 so as to' connect the armatures 5 vand6 -to theneutral point of the choke coil 55, only when the electromotive forcesgenerated by said armatures is approximately equal tc the neutral 55; anlammeter or other sui-table current indicating circuit with thearmatures 5-and 6 when the motors are operated as generators, and abattery or other suitable source of energy 95- rom which theroperatingor controlling magnet windings of all of the switches except switch 92aresupplied.

In the operation of the system, the reversing switch is iirst operatedto. cause the one or the other` of the. conducting segments 64 and 65 toengage the corresponding. stationary contact terminals, operating orcontrolling magnet windings of switches 18, 16, 17, 20, 21, and 24 beingenergized and causing closurel of the said switches for forwarddirection 'of rotation of. the motors, andthe `magnet windingsofswitches 13, A15, 18, 19,

22,4 and 23 being ener ized and causing closure of the said switc es for"reverse operation of the 'inotors The conducting segment 90 of theImaster controller is Athen moved into engagement with the correspondingop*l t e `posite stationary contact fingers `unti desired voltage, is ap-lied tothe motors, the structure andlform o the said segment beingpoint of the choke coil,

device 94 that is included in series ruptedfwhen the .such that whenit'occupies tne position a,

switch 31 is closed and `as it moves through positions b, c, and d,switches 32, 31%, and' 34 are closed successively. As -the controller ismoved to succeeding positions, swii ches 35 to 42, inclusive, close insuccession and switches 3,1 to 38 open in succession.` Since terminalsof the magnet windings ol'ilic switches 31 to 42,inclusive, areccnnectto, respectively, to 'stationary contain terminals ,67 to 78,inclusive, 4of the master controller andv also 'since this portion ofthe system ,is fullyF described in the above-mentioned patent, No]834,525, the circuits 'may be readily traced and will be readilyunderstood without further description. lf it is desired to operate themotors as generators when the vehicle upon which. the motors areeinploy'ed `is approaching a stop or is coasting or descending a grade,the conducting segment 91 of the .master controller should be moved.into engagement with the corresponding opposite stationary contactiingers, the revers- 'ing switch having iirst been moved to its ofiposition, whereupon a .circuit becomes established from one terminal ofthe battery 95 through stationary contact fingers 66, conducting.segment 9'1, contact iinger 79, and magnet windings of the switchesv26, 27, 29, and`30, back -to the other terminal ol the battery 95, theswitches 26, 27, 29, and 5,30 being thereby caused to' close. By reasonof the engagement of the conducting segment 91 with stationary contactfingers 75,'76, 77,

and 78, switches 89`to .42, inclusive, are

causedto close,.and by reasonoi4 the engage- 'ment of thesegment'91 withcontact iinger 80, the switch 43 is' also caused to close. Closing ofthe switches 26 and '43 connects the iield magnet winding 10 `betweensuitable low-voltage points ofthe. main transformer winding 1, and theclosing of switches 27, 29,

-and30' connects the iield magnet windings 1 1 and 12 in series relationbetween the ter-V minals of the armature 4, the motor comprisingarmature 4 and-'field ymagnet*winding 10 thus-serving as an exciterenerator for the iield 'magnet windings of t e remaining motors. Onetermiiialiof each oi the magnet windings of switches 25 and 28 isconnected to the stationary contact terminal 79 of the master'controllerso that when the conducting segment 91 engages,l therewith, the magnetwindings are connected to one terminal of the battery 95. The circuitconnect'ing the said magnet windings to the otherterminal `of thebattery 95 is interswitch 92 is open, the said switch beingvpermitted toclose only when the electromotive force generated by the armatures 5 and6 approximates the voltage between the neutral oint of tliechoke. coil55 and the track raii) 3'.-A When the switch 92permits; the switches 25and 28 to close, the armatures 5 and v6 become conn/ ited to the mainauto-transformer windingk through the choke coils 53, 54, and 55 and theswitches 39 to 412, inclusive, thc.arrangement of the system being thenas indicated in Fig. 3. It will be noted that when the master controlleroccupies the position c, which is the first brakingvposition, and thatusuallyv occupied by .the controller when the speed of the motors andthe generated voltage are greatest, the armatures 5 and 6 are connectedbetween high-voltage points of the main transformer winding 1, while thefield magnet winding 10 is connected between low voltage points.

As the s )eed of the motors decreases with decrease o speed of thevehicle in' connection with which they are employed, the conductingsegment 91 of the master controller should be moved to the succeedingpositions b', c', d, etc., so as to maintain the electromotive forcegenerated by the armatures 5 and 6 approXimately equal to the voltagebetween the neutral poi-'nt of the choke coil 55 and the track rail 3.As the segment 91 is moved from position b to .position g this result iseffected by causing successive closure of switches 43 to 49, inclusive,and thereby altering the connections between the field mag net winding10 and the main transformer winding 1 to cause an increase of thevoltage applied to the field magnet winding. The

circuits of the magnet' windings of switches 4 3 to 52, inclusive, maybe readily traced, since they are all similar and pass directly from oneterminal of the battery 95 through stationary contact finger 66,conducting segment 91 and contact fingers 80 to 89, in-

. clusive, to the said windings, and then back to the other terminal 95.The/ order of closure of the switches when operating the motors asgenerators may be readily understood vfrom a consideration of the chartof Fig. 2, in which the reference numerals correspond to those of theswitches, the reference letters to the positions of the vmastercontroller, and the small circles indicate the switches thatare closedin each positiorrof the controller,

As the speed of the motors decreases further, the segment 91 should bemoved through the succeeding positions h to r inclusive, switch 38 beingcaused to close and switch 42 being caused to open when the con trolleroccupies the position h', thereby reducing the voltage .at theintermediate oint of the choke coil 55. As the controler is moved topositions t', j', c, and l', a balance between the Vvolta ve generatedby the armatures 5 and 6 an the voltage at the intermediate point'of thechoke coil 55 is effected by alternately decreasingthe voltage appliedto the field magnet winding 10 and the voltage of the intermediate'piontof the choke coil 55, it being deemed unnecessary to trace the circuitsin detail for each of these steps,

motors as generators.

since the circuits may be readily traced on account of their simplicityand their similarity to those already described. 'lhe order of closureof the switches may also be readily understood from a consideration ofthc chart of Fig. 2. As the controller is moved from position m toposition i", .the switches 49, 50, 51, and 52 remain closed and thevoltage :1pplied to the field magnet winding 1 0 remains constant, whileswitches 35, 34, 3B, 32, and 31 are caused to close in succession, andswitches 38, 37, 36, and 35 are caused to open in succession, thevoltage of the intermediate point of the choke coil 55 being therebygradually reduced.

ln order that the operation of the motors as generators may cause auniform retarda.- I

tion of the vehicle upon `whiclrthe.motors are employed, and also inorder that a uniform l'dad may be maintained upon the motors, thevoltage applied to the field magnet winding 10 of the exciter and thepoints of connection of the armatures 5 and 6 to the main transformerwinding 1 are so adjusted with respect to each other that the currentsupplied by the armatures 5 and 6 to the -mam transformer winding willbe maintained substantially constant, and the order. of closure of theswitches, as indicatedby lche diagramof Fig. 2, is intended to be suchas to effect this result. ln order to provide some indication of theamount of current supplied by the armatures 5 and 6 to the maintransformer winding 1, an ammeter 94 may be included in circuit with thesaid armatures.

ln'Fig. 1, the operation of thc motors as generators is controlledmanually by means of the segmentl 91 of the master controller, but -thismaybe doneautomatically, as in Fig. 4, thus placing the operation ofthe'motors, when running as generators, beyond the' control of theattendant. Many ofthe reference numerals employed in Fig. 1 have. beenapplied to similar parts in Fig. 4, andthe system has been materiallysimplified byfrcducing the number of switches connecting to points ofsubdivi sion of the main transformer'winding, and by omitting the chokecoils 53 to 58, inclusive. which, however, it will usually be founddesirable to employ in practice.. Switches 101, to 105, inclusive, areemployed to connect the motors to the main transformer winding for motoroperation, andl the armatures 5 and 6 to the transformer winding forgenerator operation, while switches 106 to 110, inclusive, connect thefield magnet winding 10 to suitable points of subdivision of ythe maintransformer winding 1 when operating the The switches 101 to 110,inclusive, are provided. respectively, with operating or controllingmagnet windings 111 to 120, inclusive, tcrfninals of the magnet windings111 to 115,inc'lusive', being connected, respectively, to stationarycontact terminals 121 to 125, inclusive, of a of closure Iof the mastercontroller, that comprises also, movable conducting segments i126 and160 adapted to engage the stationary contact terminals of the controlleruponposition in` dicating lines c to e, inclusive, for motor operation,andeJ segment 127 adapted to engage the stationary contact terminals forgenerator'operati'on. Terminals of each oi magnet windings of theswitches 25 to 30, inclusive, are connected to contact terminal 128 ofthe master controller, and terminals ci each magnet winding 116 to 120,inclusive, arelconnected to contact terminal 129.

Switch 92, that 'is closed only when the voltage generated by thearmatures 5 and v6 approximates. that of` the point of the maintransformerI winding 1 to which the sai'd armatures are tobe' connected,is interposed, as in Fig. 1', in circuit with the magnet'windings of theswitches -25 and 28. The order switches 111 to 120,-inclusive, whenoperating the machines as generators, isvgoverned by meansofinterlocking switches 130 to 159, inclusive, comprising a correspondingnumber oi pairs of stationary contact terminals and bridging pieces thatare carried by the switches 101 to 110, inclusive -In order to cause themotors to propel the vehicle on which they may be employed, thereversing switch should. be moved to either `its forward orreverseposition, and the master controller should then be moved to one oi' thepositions indicated by the lines a to e, inclusive. It theA mastercontroller occupies the position u, a circuit is established from oneterminal of the battery 95 through contaettermin-al 162 or'ythey mastercontroller,

' conducting segment 126, stationarycontact finger 121,operating-'magnet winding 111',

i contact finger 163, conducting segment 160,

` ,'by caused to 45 tions I) to e, inclusive, switches 112 toterminal,1'64, and back -to the other terminal of thebattery 95, theswitch 101 being thereclose. p As the master controlleris moved throughthe succeeding posi- 115, inclusive, f `are closed in succession, and

switches 111 to 1 14, inclusive, open in succession, the circuitsestablished being similar to that just described for the magnet winding111. l

In order to cause the machines to operate as generators and supplycurrent to the transformer winding 1, segment127 of the mastercontroller'should be moved into engagement with'the corres ondingopposite stationary contact termina s, the reversing switch having firstbeen moved to its olf position. A circuit is then established from oneterminal of thev battery through terminal 162, seg- 'ment 127 terminal 128 and magnet windings ofiswitches 25 to 30, inclusive, it being under-Nstood, however, that the switch 92 interrupts the circuitsof the magnetwindings of switches 25 and 28, unless the voltage generated by 108closes,

the armatures 5 and 6 approximatesthat .of the point in the transformerwinding 1 to which the said armatures are to be connected. A secondcircuit is also established by way of devices bearing referencecharacters 95, 162, 127, 125, 115, 140, and 161, to energize the magnetwinding 115 and thus effect closure of the switch 105. A third circuitis'esta-blished from the master controller contact 129 by way of devices116, 146, and 161 to energize the magnet winding 116 and thus effectclosure of the switch 106. Circuits are then established as indicated inFig. 3, in case the voltage generated by the armatures 5 and 6approximates that of the point. in the transformer winding 1 to whichthe switch 105 is connected, and also in case the amount of currenttraversing the armatures 5 and 6 and operating magnet winding 167 forthe switch 1 61 does not exceed a predetermined amount,

the switch 161 serving to interrupt the circuits described when tliecurrent supplied to the transformer exceeds a predetermined amount.

lf both of l switches 92 and 161 vremain closed, another circuit willvbe established upon closure of the switch 106 fromcontact terminal.129by way of magnet winding 117 and interlocking switch 144, switch 107being thereby caused to close. If the switches 92 and 161 still remainclosed, a circuit is established, upon closure of the switch'107, fromcontact terminal 129 through magnet winding 1.18 and interlocking switch147, whereupon switch 108 closes. Vhen the switch a circuit isestablished from terminal 124 by way of devices 114, 143, 150,- and 161,switch 104..being closed because of the energization of the magnetwinding 114. When the switch 104 closes, a circuitis established fromcontact terminal 129 by way of devices 119, 151, 141, and 161 and theswitch 109 will thereupon be caused to close.

Closure of the switch 109 causes a circuit to be established by way ofdevices 123, 113, 142, 154, and 161 to energize magnetwnding 113 andthus cause the switch 103 to close. Closure of the switch 103 causes acircuit to be established' by way of devices 129, 120, 155, 137, and'1.61, Vand the switch 110 is thereupon caused to close, which, in turn,es-l tablishes the circuit of magnet winding 112 which circuit includesdevices 138 and 158. VMagnet winding 112, when energized, causesclosureof the switch 102 and a circuit is established by way of` devices121, 111, 134, and 161, switch 101 being caused to close uponenergization of the magnet winding 111. It will thus be seenthat'theswitohes ,-upplied tothe transformer winding. by the armatures 5and 6' may. remain substantially constant and ma not exceedy apredetermined' amount. his result. isfffectedby 'means of a switch161|,1WhChfis opened by the :.magnet'windng 16T-included in seriescircuit with the .armaturesand 6 when thecurrent exceeds a predeterminedamount,

When the switch 161 is elosedhand whenthe switch 9 2 is also closed, theswitches 1.01 to 110, inclusive, may c losein a predetermined orderWithout interruption, butwhen it is' '.With asubdivided transformerWinding, 'and "a plurality of dynamo-electric machines having fieldmagnet and .armature windings, one machine serving as an exciterandhavmg its armature connected to the field magnet Winding of the'remainingmaohinea of means for connecting the field magnet Winding ofthe -exciting machine andthe armatures of the remaining machine to .thetransformer Winding, and means for automaticallyso adpoints -ofconnection of the said justing the parts with t e transformer Winding'that the current supplied to the transformer winding will remainsubstantially constant.

'2. In a system of control, the combination with asubdivided transformerWinding, and

a plurality of dynamo-electric machines hav! l'ing field magnet andarmature windings, one

machine. serving as an exciter 'and having its armature connected to thefield magnet winding of the remaining machines, of means for connectingthe'iield magnet Winding of the' excitingmachine andithe armatures ofthe remaining machines to sjuch points of the substantially constant'.

3. 'In a system of control, the combination With a subdividedtransformer Winding, and

a plurality of dynamos'electric machines having field magnet and4armature windings, one

exciting machine and the armatnresofthe .y i Aremaining machines to suchpoints of the transformer .Winding that the current sup.-I

. machine serving as lan exciter and having its armature connected tothe field magnet Wind-. ing of the remaining machines, of means forconnecting the field magnet Winding of thel plied to the transformerWinding''w'villlreniain.v

substantially constant, and means foi` p'ia venting the said armaturesfrom becomingl connectedto the transformer Winding except whenAthevoltage generated thereby is -approximately the the transformerconnected.

4.. In a system with a subdivided transformer Winding', and a pluralityof dynamo-electric machines havingfield magnet and armature windings',one

Winding to which itis tobe machine serving as an exciter and having its.

armature connected -to the field magnet Winding ofthe remainin machines,ofmeans for' l connecting the fiel magnet Winding of the excitingmachines and the armature of the remainingmachine to thetransformerwindsame as that of thepoint inof control, the combinationing, means for automatically so adjusting the y .points of connection ofsaid parts ,with the transformer Winding that the current sup- 'plied-to.the transformer Winding will reiriain substantially constant, and meansforp'ref. v venting the said armatures. from becoming -connected to thetransformer Winding except lWh'en' the voltage. generated thereby visap` v, proximately the saine as that ofthe point" in the transformerwinding towhich it is to beconnected. l

-In testimony Wher'eof,I havehereu'iito sub- WILLIAM fooPER.

W itn'es'ses: l i i HOWARD L. BEACH, BIRNEY HINES.

scribed-.my naine this 24th' day of August,

transformer Winding that the current supplied. to the transformerWinding willremain

